Filter for articles of the tobacco-processing industry

ABSTRACT

Filter, method of forming filter, and filter cigarette. The filter includes at least a first filter component composed of polyethylene fibers and a second filter component composed of a granulate. The instant abstract is neither intended to define the invention disclosed in this specification nor intended to limit the scope of the invention in any way.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. §119 of German Patent Application No. 10 2005 009 608.5, filed on Feb. 28, 2005, the disclosure of which is expressly incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a filter for articles of the tobacco-processing industry, in particular for cigarettes, comprising at least one first and one second filter component.

2. Discussion of Background Information

From the commonly owned European Patent Application No. EP 1 354 522 A2 a cigarette filter and a method for producing the same are known, in which a filter component is a sort of multiple-component fiber. The length of the multiple-component fibers is shorter than the length of the filter. The multiple-component fiber comprises a mantle made of a material having a lower melting point than the core of the multiple-component fiber. In the production of the filter, at least one sort of multiple-component fibers, the length of which is shorter than the length of the filter to be produced, is formed into a rod. Subsequently, the fiber rod is heated to a temperature above the melting temperature of the mantle of the multiple-component fibers. Then, the fiber rod is cooled to a temperature below the melting temperature of the mantle of the multiple-component fibers. This renders possible a cross-linking of the multiple-component fibers to one another, rendering possible a secure bonding of the multiple-component fibers to one another. According to EP 1 354 522 A2, other components, e.g., other sorts of fibers or granulates, such as activated charcoal granulate, are provided. The first filter component in the form of multiple-component fibers then hereby sticks to the other filter components at points of contact or adheres thereto so that a corresponding support of the granulates or other sorts of fibers is rendered possible.

The disclosure of above-discussed EP 1 354 522 A2 is expressly incorporated by reference herein in its entirety.

SUMMARY OF THE INVENTION

The present invention relates to a filter featuring a homogeneous structure that can be produced simply. Furthermore, the invention relates to a corresponding filter that is cost-effective.

According to the invention, a filter for articles of the tobacco-processing industry, in particular for cigarettes, including at least one first and one second filter component. The first filter component includes polyethylene fibers and the second filter component includes a granulate. The granulate preferably has a filter effect and/or releases a flavoring agent.

Surprisingly, it was determined hereby that polyethylene fibers can also be used as binding fibers, which do not collapse into drops during heating close to the melting point of the polyethylene for a short time, but produce a connection to the other filter components so that a stable bond of the filter components is achieved.

The granulate preferably includes a powder and/or beads. Within the scope of the invention, the term granulate also covers the terms grains, aggregates of powder particles, crushed/granular or powdery material and pellets. The granulate can have an asymmetrical or a symmetrical shape. It is particularly preferred that the second filter component includes activated charcoal, ion-exchange resin and/or aluminum oxide. The second filter component can include, e.g., sugar, activated charcoal from lignite and hard coal or coke, activated charcoal from carbonized plants or plant parts such as, e.g., woods or nutshells and/or moreover silicon oxides, zeolites, hopcalites, the ion-exchange resins mentioned, preferably with functional groups, marble, limestone, foamclay, organophilically modified foamclay and phyllosilicates and aerated concrete, silica gel and titanium oxide.

A particularly stable bond in the filter is given when the components of the granulate or the granules or granulate pieces and/or the beads have a diameter of 0.3 to 0.8 mm.

A particularly good filter function is ensured when the length of the polyethylene fibers is shorter than the length of the filter. The length of the polyethylene fibers is preferably between 0.5 mm and 30 mm, in particular between 2 mm and 8 mm and in particular preferably between 3 mm and 6 mm. The length of the polyethylene fibers is preferably longer before the heat treatment than after the heat treatment.

The polyethylene fibers preferably have high-density polyethylene in the interior of the fibers and low-density polyethylene in the outer area.

By providing such polyethylene fibers, the stability of the filter produced can be clearly increased. In the interior of the fiber, for example, high-density polyethylene (HDPE) can be used. This material has a density of approx. 0.94 g/cm³ to 0.965 g/cm³.

The outer area can be low-density polyethylene (LDPE) with a density of approx. 0.915 g/cm³ to 0.935 g/cm³ or linear low-density polyethylene (LLDPE).

The fiber shape for this type of fibers can be round.

In another embodiment of the invention, the polyethylene fibers are fibers of a sort of polyethylene, e.g., LDPE fibers, HDPE fibers, LLDPE fibers or, e.g., also HMW-LDPE (HMW from high molecular weight) and UHMW-HDPE (UHMW from ultra high molecular weight).

It is hereby preferred if the degree of crystallinity of the polyethylene fibers is present in the narrowest possible range of variation. The fiber shape with these fibers is preferably round or trilobal.

As preferably provided at least one further third filter component, web-forming fibers can be provided, such as natural fibers or synthetic fibers. Natural fibers can be cellulose, cotton, flax, hemp and sheep's wool fibers in their natural length or cut to a specific length. As synthetic fibers, acetate fibers, PE fibers with a higher density than the binding fibers of polyethylene, polypropylene fibers, lyocell fibers, polylactic acid fibers (PLA) or polylactide glycolic acid fibers (PLGA fibers) are possible in various cut lengths from 1 mm to 24 mm and in various specific fiber weights from 0.7 dtex to 72 dtex. With web-forming fibers of polyethylene, preferably those should be used that have a melting point that is higher than the temperature that is used to melt the binding fibers of polyethylene. For example, LDPE fibers can be used as binding fibers, and HDPE fibers can be used as web-forming fibers.

A particularly preferred filter is given when the granulate content in the filter is 35% by weight to 95% by weight, in particular 70% by weight to 90% by weight.

It was easily possible to produce filters with a granulate content of 12 to 15 mg/mm filter and a fiber content of 1.5 to 2.5 mg/mm filter. The specification applies to filters with a diameter from 6 to 11 mm, in particular 7.8 mm (king size format). As a preferred exemplary embodiment, filters were produced with 90% activated charcoal granulate and 10% polyethylene fibers, 80% activated charcoal granulate with 20% polyethylene fibers, 70% activated charcoal granulate with 30% polyethylene fibers and 60% activated charcoal granulate and 40% polyethylene fibers. This hereby refers to % by weight.

Further granulates or beads can be added to the activated charcoal granulate, and other fibers can also be added to the polyethylene fibers. Filters can also be produced with PE fibers and only beads.

Preferably the polyethylene fibers are binding fibers and bound to one another and to the granulate. However, not every binding fiber is necessarily also hereby bound to another binding fiber. In fact, it can be that a binding fiber is bound to several granulates or granulate parts, and again other binding fibers are bound to the granulates. Within the scope of the invention, the term bound means in particular adhered and sticking. A chemical bond can prevail here or a mechanical bond, e.g., through a force-locking engagement or a positive engagement.

The PE fibers are preferably fibers solidified again after a melting, which fibers bind the granulate located in the vicinity during the melting of the fibers to one another.

According to the inventive method for producing a filter, which is described above, the method includes:

-   -   Mixing the first filter component with the second filter         component;     -   Forming a filter rod out of the mixture;     -   Heating the filter rod to at least approximately the melting         temperature of the first filter component;     -   Cooling the filter rod; and     -   Cutting the filter rod to length into filters.

The heating of the filter rod preferably occurs at a temperature above the melting temperature of the first filter component, e.g., so briefly that this filter component does not completely melt through. However, it is also possible through heat treatment of the filter rod produced to let the polyethylene fibers melt completely and to let the material of polyethylene bind to the granulate components on the filter so that bonds develop between the individual granules, whereby it is even possible that the fiber is deformed. The polyethylene fibers preferably start to melt or at least soften.

Through polyethylene fibers as binding medium it is possible to load them with a maximum amount of granulates and similar materials or substances.

The mixing preferably takes place before and/or during the shaping of the filter rod.

The present invention is directed to a filter including at least a first filter component composed of polyethylene fibers and a second filter component composed of a granulate.

According to a feature of the invention, the filter can be structured and arranged for articles of the tobacco-processing industry.

In accordance with another feature of the instant invention, the filter can be structured and arranged for a cigarette.

The granulate can include at least one of powder and beads. Further, constituents of the beads can have a diameter of 0.3 mm to 0.8 mm.

The granulate may include activated charcoal, ion-exchange resin and/or aluminum oxide. Further, constituents of the granulate have a diameter of 0.3 mm to 0.8 mm.

Moreover, the filter can have a length, and a length of the polyethylene fibers may be shorter than the length of the filter. In this regard, the length of the polyethylene fibers can be between 0.5 mm and 30 mm, preferably, the length of the polyethylene fibers is between 2 mm and 8 mm, and most preferably, the length of the polyethylene fibers can be between 3 mm and 6 mm.

According to another feature of the invention, the polyethylene fibers may have high-density polyethylene in an interior region of the fibers and low-density polyethylene in an outer region of the fibers.

In accordance with still another feature of the present invention, the polyethylene fibers may be fibres of one sort of polyethylene.

The filter according to the instant invention can further include a third filter component, and the third filter component can be composed of web-forming fibers.

According to still another feature of the present invention, a content of the granulate in the filter is between 35% by weight to 95% by weight, and preferably, between 70% by weight to 90% by weight.

The polyethylene fibers may be binding fibers structured and arranged to bind at least one of to one another and to the granulate.

Further, the polyethylene fibers can be solidified fibers after having been melted, whereby the fibers bind the granulate to one another.

The present invention is directed to a method for producing the above-noted filter. The method includes mixing the first filter component with the second filter component, forming a filter rod out of the mixed first and second filter components, heating the filter rod to at least approximately a melting temperature of the first filter component, cooling the filter rod, and cutting the filter rod into filter lengths.

According to the invention, the mixing occurs at least one of before and during the forming of the filter rod.

The present invention is directed to a filter cigarette having the above-described filter.

Other exemplary embodiments and advantages of the present invention may be ascertained by reviewing the present disclosure and the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is further described in the detailed description which follows, in reference to the noted drawing by way of a non-limiting example of an exemplary embodiment of the present invention, and wherein:

The FIGURE shows a scanning electron microscope image of a section through a filter according to the invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiment of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show structural details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description taken with the drawing making apparent to those skilled in the art how the present invention may be embodied in practice.

The FIGURE shows a scanning electron microscope image of a section through a filter according to the invention. The filter is composed of 90% by weight granulate of activated charcoal and 10% by weight polyethylene fibers. The polyethylene fibers are labeled by reference number 1 and the activated charcoal granulate is labeled by reference number 2. An incipient melting point is shown by reference number 3, and this incipient melting point of two polyethylene fibers 2 is discernible within the drawn circle. In the lower area of the scanning electron microscope image a scale is shown that extends over the length of one millimeter.

For producing the filter reference is made in particular to commonly owned European Patent Application No. EP 1 464 241 A1. In this patent application the production of a web for the production of filters of the tobacco-processing industry and a filter rod production device and the method for producing a filter rod are described in detail. Reference is made in particular to FIGS. 13, 15 and 17 through 20 and the relevant figure descriptions for mixing the filter components and forming a web on a suction rod conveyor. In this way, one skilled in the art is aware that a rod forming device is connected to the suction rod conveyor, which rod forming device then, for example, can be followed by a heat treatment device or the heating step. The disclosure of the above-discussed EP 1 464 241 A1 is expressly incorporated by reference herein in its entirety.

The mixing of the filter materials can preferably take place before the final separation of the filter materials or a part thereof. The mixing process can, however, also take place shortly before the insertion into a fluidized bed.

Alternatively, it is possible to produce a filter rod and the filters on an AF/AC/KDF machine of the applicant. With this known machine, filters are produced from endlessly long fibers, e.g., of polyethylene. In this regard, granulate, such as, e.g., activated charcoal granulate, is inserted in the AC module into the fibers so that a corresponding intermingling takes place. A corresponding AF/KDF machine is known from European Patent No. EP 0 919 144 B1, the disclosure of which is expressly incorporated by reference herein in its entirety. The AF/AC/KDF machine is then designed such that the granulate feed device is arranged between the KDF part and the AF part. For example, further filter materials can also be added, as is shown in FIG. 2 of DE 103 52 152.6 of the applicant. There further filter materials are inserted in an endless fiber rod or in an endless fiber tow. According to the present invention, then, e.g., the cellulose ester fibers of which the fiber tow is formed according to DE 103 52 152.6 are to be replaced by polyethylene fibers.

The polyethylene fibers are preferably those of the type TWR04805-1 crimped with 33 crimps/10 cm, 6.7 dtex or 8.25 dtex, 5 mm length from FiberVisions. The binding fibers preferably have an essentially equal length. The melting point is 162° C. Polyethylene fibers of the type Polysteen Cut, uncrimped, 4.5 dtex, 5 mm long, melting point 132° C., from Polysteen can also be used.

The filter shown in the FIGURE was produced, e.g., according to a method that is described in the above-discussed commonly owned EP 1 464 241 A1. The filter rod produced accordingly around which a casing material is wound moves through a microwave heater at a speed of 20 m per minute following the forming assembly. Following the microwave heater, the casing material, in this exemplary embodiment, cigarette paper, has a surface temperature of 140° C.

It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the present invention has been described with reference to an exemplary embodiment, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to particular means, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims. 

1. A filter comprising: at least a first filter component composed of polyethylene fibers and a second filter component composed of a granulate.
 2. The filter in accordance with claim 1, wherein the filter is structured and arranged for articles of the tobacco-processing industry.
 3. The filter in accordance with claim 1, wherein the filter is structured and arranged for a cigarette.
 4. The filter in accordance with claim 1, wherein the granulate comprises at least one of powder and beads.
 5. The filter in accordance with claim 4, wherein constituents of the beads have a diameter of 0.3 mm to 0.8 mm.
 6. The filter in accordance with claim 1, wherein the granulate comprises activated charcoal, ion-exchange resin and/or aluminum oxide.
 7. The filter in accordance with claim 1, wherein constituents of the granulate have a diameter of 0.3 mm to 0.8 mm.
 8. The filter in accordance with claim 1, wherein the filter has a length, and a length of the polyethylene fibers is shorter than the length of the filter.
 9. The filter in accordance with claim 8, wherein the length of the polyethylene fibers is between 0.5 mm and 30 mm.
 10. The filter in accordance with claim 9, wherein the length of the polyethylene fibers is between 2 mm and 8 mm.
 11. The filter in accordance with claim 10, wherein the length of the polyethylene fibers is between 3 mm and 6 mm.
 12. The filter in accordance with claim 1, wherein the polyethylene fibers have high-density polyethylene in an interior region of the fibers and low-density polyethylene in an outer region of the fibers.
 13. The filter in accordance with claim 1, wherein the polyethylene fibers are fibres of one sort of polyethylene.
 14. The filter in accordance with claim 1, further comprising a third filter component.
 15. The filter in accordance with claim 14, wherein the third filter component is composed of web-forming fibers.
 16. The filter in accordance with claim 1, wherein a content of the granulate in the filter is between 35% by weight to 95% by weight.
 17. The filter in accordance with claim 16, wherein the content of granulate in the filter is between 70% by weight to 90% by weight.
 18. The filter in accordance with claim 1, wherein the polyethylene fibers are binding fibers structured and arranged to bind at least one of to one another and to the granulate.
 19. The filter in accordance with claim 1, wherein the polyethylene fibers are solidified fibers after having been melted, whereby the fibers bind the granulate to one another.
 20. A method for producing a filter in accordance with claim 1, the method comprising: mixing the first filter component with the second filter component; forming a filter rod out of the mixed first and second filter components; heating the filter rod to at least approximately a melting temperature of the first filter component; cooling the filter rod; and cutting the filter rod into filter lengths.
 21. The method in accordance with claim 20, wherein the mixing occurs at least one of before and during the forming of the filter rod.
 22. A filter cigarette having a filter in accordance with claim
 1. 